Organophosphorus insecticides mineralizing endophytic and rhizospheric soil bacterial consortium influence eggplant growth-promotion.

This study was aimed to evaluate eggplant's growth-enhancing activity of chlorpyrifos and diazinon-degrading endophytic and rhizospheric soil bacteria isolated from cauliflower and tomato roots and the rhizospheric soil of rice roots, respectively. The identified endophytes belong to the Acinetobacter, Enterobacter and Klebsiella genera, while rhizospheric soil isolates belong to Pantoea, Acinetobacter, Kosakonia, Morganella, Enterobacter, and Klebsiella genera with species variation and genetic distances. All the strain's consumed 100% (50 mg/5 mL) chlorpyrifos and diazinon after 14 days of exposure, except for Pantoea sp. HSTU-Sny4 (84%) and Kosakonia sp. HSTU-ASn39 (42%). The strain's exhibited N-fixation, P-solubilization, indole-3-acetic acid (IAA), and ACC-deaminase production capabilities. The individual strain's and consortium treatment enhanced eggplant growth at germination, seedling, vegetative and reproductive stages. Plant growth-promoting genes, e.g., nif-cluster, chemotaxis, phosphates, sulfur, abiotic stress, chemotaxis, biofilm formation and organophosphorus insecticide-degrading genes were annotated in Klebsiella sp. HSTU-Sny5 and Morganella sp. HSTU-ASny43 genomes. Importantly, the mixed consortium supplemented with 40% urea-treated eggplants demonstrated similar growth parameters compared to the 100% urea eggplants. Plenty of insecticide-degrading proteins belonged to HSTU-Sny5 and HSTU-ASny43 strain's and had interacted with 100 different insecticides as confirmed in virtual screening. This research has a significant role in reducing the application of chemical fertilizer and bioremediation of pesticides in agriculture.

Unveiling lignocellulolytic trait of a goat omasum inhabitant Klebsiella variicola strain HSTU-AAM51 in light of biochemical and genome analyses.

Klebsiella variicola is generally known as endophyte as well as lignocellulose-degrading strain. However, their roles in goat omasum along with lignocellulolytic genetic repertoire are not yet explored. In this study, five different pectin-degrading bacteria were isolated from a healthy goat omasum. Among them, a new Klebsiella variicola strain HSTU-AAM51 was identified to degrade lignocellulose. The genome of the HSTU-AAM51 strain comprised 5,564,045 bp with a GC content of 57.2% and 5312 coding sequences. The comparison of housekeeping genes (16S rRNA, TonB, gyrase B, RecA) and whole-genome sequence (ANI, pangenome, synteny, DNA-DNA hybridization) revealed that the strain HSTU-AAM51 was clustered with Klebsiella variicola strains, but the HSTU-AAM51 strain was markedly deviated. It consisted of seventeen cellulases (GH1, GH3, GH4, GH5, GH13), fourteen beta-glucosidase (2GH3, 7GH4, 4GH1), two glucosidase, and one pullulanase genes. The strain secreted cellulase, pectinase, and xylanase, lignin peroxidase approximately 76-78 U/mL and 57-60 U/mL, respectively, when it was cultured on banana pseudostem for 96 h. The catalytically important residues of extracellular cellulase, xylanase, mannanase, pectinase, chitinase, and tannase proteins (validated 3D model) were bound to their specific ligands. Besides, genes involved in the benzoate and phenylacetate catabolic pathways as well as laccase and DiP-type peroxidase were annotated, which indicated the strain lignin-degrading potentiality. This study revealed a new K. variicola bacterium from goat omasum which harbored lignin and cellulolytic enzymes that could be utilized for the production of bioethanol from lignocelluloses.